Skin treatment apparatus with adaptive motion feedback

Abstract

A skin treatment device (100) comprises: —a housing (101); —a treatment action performer (110) arranged within the housing (101) for performing a treatment action on the user's skin (2); —a speed sensor (120) for sensing a relative speed between the housing and the user's skin; —a speed feedback signalling device (400); —a control device (140) receiving an output signal from the speed sensor. The control device controls the speed feedback signalling device if the output signal received from the speed sensor is outside a tolerated displacement speed range (R). The tolerated displacement speed range is adapted to the skills of the user to move the device over the skin surface with a constant speed. If the user's skills are relatively low, the control device increases the magnitude of the tolerated displacement speed range.

The invention claimed is: 
     
       1. Skin treatment device comprising:
 a housing whose shape and size are suitable for being held by a human hand; 
 a treatment action performer associated with the housing for performing a treatment action on a user's skin; 
 a speed sensor for sensing a relative displacement speed (V) between the housing and the user's skin in a device displacement direction (X) parallel to a surface of the skin; 
 a speed feedback signalling device comprising a signal generator for generating a signal perceivable by a human; and 
 a control device provided with an associated memory containing information defining a tolerated displacement speed range (R) having an upper threshold (V 1 ) and a lower threshold (V 2 ),
 wherein the control device is coupled to receive an output signal (S V ) from the speed sensor and is coupled to provide a control signal to the speed feedback signalling device, 
 wherein the control device is adapted to compare the speed sensor output signal (S V ) with said upper threshold (V 1 ) and with said lower threshold (V 2 ), and to control the speed feedback signalling device such as to generate a first feedback signal when the speed sensor output signal (S V ) indicates that the relative displacement speed (V) is higher than said upper threshold (V 1 ) and to generate a second feedback signal when the speed sensor output signal (S V ) indicates that the relative displacement speed (V) is lower than said lower threshold (V 2 ), 
 wherein the control device is further adapted to monitor a parameter indicative of a degree of a user's ability to move the skin treatment device at a correct speed, 
 wherein the control device is further adapted to set a relatively large magnitude of, or increase the magnitude of, the tolerated displacement speed range (R) if said parameter indicates a relatively low degree of said user's ability, and 
 wherein the control device is further adapted to set a relatively small magnitude of, or decrease the magnitude of, the tolerated displacement speed range (R) if said parameter indicates a relatively high degree of said user's ability. 
 
 
     
     
       2. Skin treatment device according to  claim 1 ,
 wherein the skin treatment device has a target operational range (OR) of the relative displacement speed (V), the target operational range having a target operational upper limit (OV 1 ) and a target operational lower limit (OV 2 ); 
 wherein the control device is further adapted to calculate the upper threshold (V 1 ) according to the formula V 1 =OV 1 +TM 1  and to calculate the lower threshold (V 2 ) according to the formula V 2 =OV 2 −TM 2 , in which: 
 V 1  indicates the value of the upper threshold, 
 V 2  indicates the value of the lower threshold, 
 OV 1  indicates the value of the target operational upper limit, 
 OV 2  indicates the value of the target operational lower limit, 
 TM 1  indicates an upper tolerance margin, and 
 TM 2  indicates a lower tolerance margin; and 
 wherein the control device is further adapted to increase at least one of said upper and lower tolerance margins (TM 1 , TM 2 ) for users with a relatively low degree of said user's ability, and to decrease at least one of said upper and lower tolerance margins (TM 1 , TM 2 ) for users with a relatively high degree of said user's ability. 
 
     
     
       3. Skin treatment device according to  claim 1 , wherein the first feedback signal and the second feedback signal are mutually different. 
     
     
       4. Skin treatment device according to  claim 1 , wherein the control device is adapted to analyse the speed sensor output signal (S V ) and to rate the parameter indicative of the degree of said user's ability in real time on the basis of the outcome of this analysis. 
     
     
       5. Skin treatment device according to  claim 4 , wherein the control device is adapted to analyse the speed sensor output signal (S V ) by obtaining and analysing a frequency profile of the speed sensor output signal. 
     
     
       6. Skin treatment device according to  claim 4 , wherein the control device is adapted to analyse the speed sensor output signal (S V ) by measuring and analysing an amplitude of the speed sensor output signal at a certain frequency or within a certain frequency band or above a certain cut-off frequency. 
     
     
       7. Skin treatment device according to  claim 1 , wherein the control device is adapted to monitor a number of times and/or an amount of time that the device has actually been used, and to decrease the magnitude of the tolerated displacement speed range (R) as the number of times that the device has actually been used increases and/or the amount of time the device has actually been used increases, respectively. 
     
     
       8. Skin treatment device according to  claim 1 , wherein the control device is adapted to store, in the memory, data defining the magnitude of the tolerated displacement speed range (R). 
     
     
       9. Skin treatment device according to  claim 2 , wherein the control device is adapted to store, in the memory, data defining the values of the upper and lower tolerance margins (TM 1 , TM 2 ). 
     
     
       10. Skin treatment device according to  claim 2 , wherein the control device is adapted to store, in the memory, data defining the target operational range (OR). 
     
     
       11. Skin treatment device according to  claim 10 , wherein the control device is adapted to adapt the target operational range (OR). 
     
     
       12. Skin treatment device according to  claim 11 , further comprising a skin-type sensor for determining a skin type of the user's skin, and wherein the control device is adapted to adapt the target operational range (OR) to the skin type determined by the skin-type sensor. 
     
     
       13. Skin treatment device according to  claim 1 , wherein the control device is adapted to adapt a power level of the treatment action performer in conjunction with an adaptation of the magnitude of the tolerated displacement speed range (R), wherein an increase of the magnitude of the tolerated displacement speed range (R) is associated with a reduction of the power level. 
     
     
       14. Skin treatment apparatus comprising the skin treatment device according to  claim 1 .